Leonard Case Jr. (January 27, 1820, Cleveland – January 6, 1880) was a philanthropist who endowed the Case School of Applied Science (later Case Institute of Technology, later merged with Western Reserve University to become Case Western Reserve University). He graduated from Yale University in 1842. Though he was ill for all his life, he was devoted to academic affairs.
Leonard never married. His father was also named Leonard; and William Case was his elder brother.